2. LEARNING OBJECTIVE
Explain how the Quantum
Mechanical Model of the atom
describes the energies and
positions of the electrons
3. Learning Goals
Compare the Bohr and quantum mechanical
models of the atom.
Explain the impact of de Broglie’s wave particle
duality and the Heisenberg uncertainty principle on
the current view of electrons in atoms.
Identify the relationships among a hydrogen
atom’s energy levels, sublevels, and atomic
orbitals.
4. Bohr’s Model of the Atom
Einstein’s theory of light’s dual nature
accounted for several unexplainable
phenomena, but it did not explain why
atomic emission spectra of elements
were discontinuous.
5. Bohr’s Model of the Atom
In 1913, Niels Bohr, a Danish
physicist working in Rutherford’s
laboratory, proposed a quantum
model for the hydrogen atom that
seemed to answer this question.
6.
7. Bohr’s Model of the
Atom
The lowest allowable energy state of
an atom is called its ground state.
When an atom gains energy, it is in an
excited state.
8. Bohr’s Model of the Atom
Bohr suggested that an electron moves around the
nucleus only in certain allowed circular orbits.
9. Bohr’s Model of the Atom
Each orbit was given a
number, called the quantum
number.
Bohr orbits are like steps of a
ladder, each at a specific
distance from the nucleus and
each at a specific energy.
10. Bohr’s Model of the Atom
Hydrogen’s single electron is in the n =
1 orbit when it is in the ground state.
When energy is added, the electron moves
to the n = 2 orbit.
11. Bohr’s Model of the Atom
The electron releases energy as it falls
back towards the ground state.
12. Quantum Mechanical
Model
The only quantity that can be
known is the probability for an
electron to occupy a certain
region around the nucleus.
13. Quantum Mechanical
Model
In the quantum-mechanical model, a
number and a letter specify an orbital.
The lowest-energy orbital is called
the 1s orbital.
It is specified by the number 1
and the letter s.
14. Hydrogen’s Atomic Orbitals
The number is called the Principal
quantum number (n) and it
indicates the relative size and
energy of atomic orbitals.
n specifies the atom’s major energy
levels, called the principal energy
levels.
16. Hydrogen’s Atomic Orbitals
Each energy sublevel relates to orbitals of different
shape.
s
s, p
s, p, d
s, p, d, f
17.
18.
19.
20.
21. S Block (Groups 1 and 2): The s block can hold a maximum of
2 electrons. Elements in Group 1 have one electron in their
their outermost shell (s orbital), while those in Group 2 have
2 have two electrons.
P Block (Groups 13-18): The p block can hold a maximum of
6 electrons. Elements in Groups 13 to 18 have electrons
electrons filling the p orbitals in their outermost shells.
shells.
D Block (Transition Metals): The d block can hold a
maximum of 10 electrons. Transition metals, found in the d
the d block, have their outermost electrons filling the d
d orbitals.
F Block: The f block can hold a maximum of 14 electrons.
Kung nasan na orbit lang ang electron dun lang sya allowed mag move or umikot.
Sa buod, ang pahayag ay naglalarawan ng proseso kung saan ang isang elektron, matapos ma-excite patungo sa mas mataas na antas ng enerhiya, ay bumabalik sa mas mababang, mas stable na antas ng enerhiya, at naglalabas ng sobrang enerhiya sa anyo ng heat or light o iba pang uri ng electromagnetic radiation.
Instead of providing an exact location for an electron, quantum mechanics gives us a wave function that describes the probability of finding the electron in different locations.
